Since you have not made any cell references or given any values, I will make
the comparison between A1 and B1 with B1 being the value to check and see if
it is lower than A1. In B1, create the conditional format as follows:

CONDITION 1: Set to "Formula Is" and then add the following formula:
=AND(B1<"",B1=A1*.3,B1<=A1*.5)
Then set your highlight to red

"juanpablo" wrote:

I need to highlight in red if a specific value is between 30% and 50% lower.

Thanks

JPG